1. Field of the Invention
The present invention relates to an organic electroluminescence display device.
2. Description of the Related Art
In recent years, image display devices (hereinafter referred to as “organic EL (Electro-Luminescence) display devices”) using a self-luminous body called an organic light-emitting diode (OLED) have been put to practical use. Since the self-luminous body is used, the organic EL display devices are superior in terms of visibility and response speed, compared to a related-art liquid crystal display device, and in addition, a further reduction in thickness is possible because an auxiliary lighting device such as a backlight is not necessary.
In a so-called top-emission display device of the organic EL display devices, light is emitted toward the side of a substrate on which elements are formed. In the top-emission display device, an upper electrode of the upper electrode and a lower electrode as two electrodes that interpose an organic layer including a light-emitting layer therebetween is an electrode that covers the whole surface of a display area where the organic layer is formed, and is formed of a transparent conductive material. The upper electrode is desirably formed thinner for improving the light transmittance. However, as the upper electrode becomes thinner, the resistance value rises and a voltage drop occurs. For this reason, unevenness of luminance is likely to occur between an edge portion of the display area and a central portion of the display area.
In an organic EL display device disclosed in JP 2010-027504 A, a routed wiring provided in a non-display area on the outside of a display area of a sealing substrate that is arranged to face an element substrate is connected with a cathode of the element substrate, for achieving the low resistance of a cathode as an upper electrode and achieving a narrow picture-frame. Moreover, in an organic EL display device disclosed in JP 2008-511100 A, when two or more light-emitting layers of different colors are stacked to emit light, an intermediate connection layer is provided between the light-emitting layers.